The invention relates to a twist prevention system for turbomachinery.
A plurality of variously designed turbomachinery is already known from the prior art. The turbomachinery has a housing through which axial flow is possible, on which at least a guide wheel is fastened, which has a plurality of circumferentially arranged adjacent guide vanes. The guide vanes have, at their radially inner end, an end portion, which, in particular in gas turbines, can be connected with a seal carrier. The seal carrier is used for sealing a gap between the guide vane, in particular the end portion, and a rotor of the turbomachine.
Guide vanes, in particular those which can be adjusted about their longitudinal axis are, on their radial end, connected to an inner ring segment and end portion, in particular releasably so. In one embodiment, a radially inner end of the guide vane, such as, for example, a pin provided on a vane blade, can be accommodated in a bushing, which is fixed by the inner ring segment. The inner ring segment, in turn, is connected to a seal carrier segment, in particular releasably.
In particular in the operation of such gas turbines, the problem occurs that the inner ring segments can twist together, or the inner ring formed by them can twist with respect to the seal carrier segments and the seal carrier formed therefrom.
From designs from internal practice, versions are known in which a relative rotation between an inner ring segment and a seal carrier segment is prevented by a bolt connection. A bolt connection has the disadvantage that an additional process step in the form of manufacturing a hole is required in the inner ring segment and the seal carrier segment. Furthermore, the inner ring segment and the seal carrier segment must be designed so that sufficient space is available to receive the bolt, which is particularly a problem when the inner ring segment and the seal carrier segment have small dimensions.
Generally, this entails the need for an advantageous twist prevention system for the turbomachinery, in particular a twist prevention system between a segmented inner ring and a seal carrier of a gas turbine.
Therefore, a task of an embodiment of the present invention is to provide an improved twist prevention system for a turbomachine, particularly improved twist prevention between a segmented inner ring and a seal carrier of a gas turbine.
According to the invention, a twist prevention system for turbomachinery is provided, which comprises at least a first ring segment pair and a second ring segment pair. In one embodiment, the turbo machine has further first and/or second and/or additional ring segment pairs. In particular, an outer ring and an inner ring fixed thereto of a turbo machine can, according to the present invention, consist of a first ring segment and a pair or several pairs of the second ring segment, or a second ring segment pair and one or more pairs of the first ring segment. Similarly, an outer ring and an inner ring fixed thereto of a turbo machine, according to the present invention, can have two or more first and two more second segment pairs, in particular made therefrom, which in an embodiment can be alternately arranged in the circumferential direction.
The ring or the first segment pairs each comprise a first radially inner ring segment and a radially outer first ring segment. The one, or the second ring segment pairs, in each case have a second radially inner ring segment and a radially outer second ring segment.
In one embodiment of the present invention, the radially outer ring segment pairs can be the inner ring segment pairs of a gas turbine, and the radially inner ring segment pairs thereon, in particular releasably fastened, in particular form-fitting radially and/or axially fixed, can be the seal carrier segment pairs of the gas turbine. Accordingly, a twist prevention system between the inner ring and a segmented seal carrier of a gas turbine is a preferred application of the present invention, so that these will be explained in detail, in particular with reference thereto. The invention is not limited to such a twist prevention system, but generally relates to a twist prevention system between a segmented outer ring and an, in particular radially and/or axially fixed, inner ring of a turbomachine.
The ring segment pairs have mutually facing faces. According to the invention, it is provided that a portion of the face of the first radially inner ring segment covers a portion of the face of the second radially outer ring segment in the radial direction.
By such radial overlap of the first radially inner ring segment and the second radially outer ring segment, twisting of the first radially inner ring segment is, in one embodiment, limited in a form-fitting manner relative to the first radially outer ring segment, and is, in particular, at least substantially-prevented. In particular, twisting can be limited or prevented, in that a movement is prevented, for example, of the first radially inner ring segment, since the portion of the face of the first radially inner ring segment is in a form-fit connection with the portion of the face of the second radially outer ring segment.
Thus, in contrast to known designs, no bolted connections are necessary any longer to prevent relative twisting between the first radially inner and first radially outer ring segments of the first ring segment pair and/or between the second radially inner and second radially outer ring segments of the second ring segment pair. In one embodiment, a separate work step for making the holes for the bolt connection in the ring segments can be dispensed with, which also can reduce the manufacturing cost of the twist prevention system. Additionally or alternatively, relative twisting of the ring segments to each other, in which the inner and outer ring segments of the ring segment pairs are small in size, can be prevented.
The faces of a ring segment are understood to mean the two end sides of a ring segment which restrict it in the circumferential direction. The faces extend transversely, in particular perpendicularly, in the circumferential direction.
In one embodiment, a distance of a radially outer contact surface of the first and/or second radially inner ring segment and a radially inner mating contact surface of the first and/or second radially outer ring segment from a central axis of the turbomachine in the circumferential and/or axial direction, can, at least substantially, remain constant. Such a configuration of the inner and outer ring segments offer the advantage that they can be manufactured in a simple manner, thereby reducing manufacturing costs. A contact surface of the first and/or second radially inner ring segment and mating contact surface of the first and/or second radially outer ring segment and in particular the surfaces of the first and/or second radially inner ring segment and the first and/or second radially outer ring segment are described, which in the assembled state of the twist prevention system or the turbo machine are in contact with each other.
The twist prevention system, as described above, comprises a plurality of ring segment pairs. In a twist prevention system, in which more than two ring segment pairs are present, in addition to the first and second ring segment pairs, at least a third ring segment pair may be present. The third ring segment pair may be located adjacent to the first or the second ring segment pair. Furthermore, the third ring segment pair can comprise a third radially inner ring segment and a third radially outer ring segment. A portion of the face of the third radially inner ring segment of the third ring segment may overlap a portion of the face of the first or second radially outer ring segment in the radial direction. By providing the third ring segment pair, a relative twisting between the radially inner and the radially outer ring segments of the respective ring segment pairs can be further prevented. In an alternative embodiment, the third ring segment pair is formed such that a portion of the face of the third radially inner ring segment does not overlap the portion of the face of the first and second radially outer ring segment. Thus, by a radial shoulder between said first and second ring segment pairs, a twisting of the third or further ring segment pairs, or the inner relative to the outer ring, is, in particular, prevented.
In one embodiment, the twist prevention system can be formed in such a way that all the circumferentially adjacent ring segment pairs are each formed in such a way that a portion of the face of a radially inner segment of a ring segment pair overlaps a portion of the face of a radially outer segment of an adjacent ring segment pair in the radial direction. With such a design of twisting prevention system, relative twisting can be particularly effectively limited or prevented.
In the twist prevention system, the distance of a radially inner lateral surface of the first radially inner ring segment and a radially inner lateral surface of the second radially inner ring segment and/or the distance between a radially outer lateral surface of the first radially outer ring segment and a radially outer lateral surface of the second radially outer ring segment, to the central axis of the turbomachine, at the mutually facing faces, can be equal, so that the lateral surfaces, at least substantially, steplessly enter into one another.
In a preferred embodiment, the first and/or second and/or third radially inner ring segment can be a seal carrier segment. Furthermore, the first and/or second and/or third radially outer ring segment may also be an inner ring segment. The inner ring segment may be coupled with one or more guide vanes, and in particular be connected fixedly or movably and/or permanently or releasably. Additionally or alternatively, the inner ring segment can be connected with the seal carrier segment, in particular releasably.
The seal carrier segment and the inner ring segment can be connected together either releasably with a form-fit connection, in particular axially and/or radially fixed to one another. In particular, for establishing the connection between the seal carrier segment and the inner ring segment, a projection into a recess can be used. The projection may be disposed at one of the inner ring segment and the seal carrier segment. Accordingly, the receptacle can be arranged on the other of the inner ring segment and the seal carrier segment.
The connection between the inner ring segment and the seal carrier segment can be arranged in adjacent ring segment pairs offset from each other in the radial direction. Thus, the projection and the wall portions bounding the receptacle in the adjacent ring segment pairs can be arranged offset from each other in the radial direction. In particular, the projection and the receptacle or the receptacle-wall-defining portions of the first ring segment pair in the radial direction may be arranged closer to or farther from the central axis of the turbomachine than the projection and the receptacle or the receptacle-wall-defining portions of the second ring segment pair.
A seal may be provided between the inner ring segment and the seal carrier segment. The seal may be formed with a w-shaped profile. The seal may further be arranged in a cavity defined by the inner ring segment and the seal carrier segment. The provision of the seal has the advantage that a leakage current can be reduced, thereby improving the efficiency of the turbomachine. Here, a leakage current is possible, as, in the above-mentioned connection between the inner ring segment and the seal carrier segment, the projection and the receptacle are shaped so that a small gap exists between them, through which the leakage current can flow.
The seal can be arranged in a radial direction closer to the central axis of the turbomachine than the connection between the inner ring segment and the seal carrier segment.
The cavity, and the wall portions of the inner ring segment and/or the seal carrier segment bounding the cavity for accommodating the seal, can be arranged offset from each other in adjacent ring segment pairs in the radial direction. In particular, the cavity and the wall portions of the inner ring segment and the seal carrier segment of the first ring segment pair in the radial direction may be arranged closer to or farther from the central axis of the turbomachine than the wall portions of the inner ring segment and the seal carrier segment of the second ring segment pair.
The twist preventing system described above can be used in a gas turbine, in particular an aircraft engine having at least one compressor and/or turbine stage. However, the use of the twist prevention system is not limited to the gas turbine and aircraft engine, but can also be used in other turbomachinery.
Further features and advantages will become apparent from the exemplary embodiment and the drawings.